Automatic sheet feeding apparatus with clutch

ABSTRACT

An automatic sheet feeding apparatus includes a pick-up mechanism, a sheet transporting mechanism, a power source and a clutch. The sheet transporting mechanism transports a sheet picked up by the pick-up mechanism through and out of a passageway. The power source for driving the pick-up mechanism includes a power output shaft and a first transmission gear for respectively outputting and transmitting power. The clutch includes a second transmission gear and a power coupling component. The second and first transmission gears are disposed coaxially. The power coupling component is coaxially disposed between the first transmission gear and the second transmission gear and is coupled to the first transmission gear. The power coupling component reciprocates back and forth along an axis to selectively couple and drive the second transmission gear. The second transmission gear is coupled to the pick-up mechanism, and the power source selectively drives the pick-up mechanism through the clutch.

This application claims priority of No. 098106926 filed in Taiwan R.O.C. on Mar. 4, 2009 under 35 USC 119, the entire content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an automatic sheet feeding apparatus, and more particularly to an automatic sheet feeding apparatus having a clutch for controlling a sheet transporting operation.

2. Related Art

A pick-up type automatic sheet feeding apparatus used in a conventional scanner usually includes a pick-up roller, a separation roller and a plurality of sheet transporting rollers. The pick-up roller is driven up and down to pick up a sheet and feed it to the separation roller. Because the pick-up roller and the separation roller need to be rotated intermittently and alternately and the sheet transporting rollers have to be continuously rotated, the assembly of the pick-up roller and the separation roller and the set of the sheet transporting rollers have to be separately driven. To meet this requirement, two motors can be adopted to drive the assembly of the pick-up roller and the separation roller and the set of the sheet transporting rollers, respectively. Consequently, the product cost is significantly increased. Therefore, a gear clutch device is conventionally adopted to achieve the function of separately driving the two sets of mechanisms.

The conventional gear clutch device controls the gear mesh between two transmission gears by adopting a solenoid to adjust the distance between the centers of these two transmission gears. Thus, the teeth of the transmission gears may collide with each other and are thus worn out in a short time, and the precision thereof degrades.

In a rocking gear clutch device, a driving gear and a plurality of idle gears are mounted on a V-shape rocker arm, and the inertial of the rotating driving gear swings the rocker arm to a first position where one of the idle gears meshes with one output gear, and a second position where another one of the idle gears meshes with the output gear so that two outputs may be obtained. A solenoid may be used to push the rocker arm to separate the idle gear from the output gear and thus to cut off the power transmission between the driving gear and the output gear.

In the gear clutch device mentioned hereinabove, all the gears are positioned in a vertical plane. Thus, the weights of the parts and the properties of the spring must be considered when such gear clutch device is designed to avoid any malfunction.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an automatic sheet feeding apparatus having a clutch for effectively solving the problem of gear clash. In addition, engineers may design such automatic sheet feeding apparatus without taking into consideration of the weights of machine components and spring characteristics.

To achieve the above-identified object, the invention provides an automatic sheet feeding apparatus including a pick-up mechanism, a sheet transporting mechanism, a power source and a clutch. The pick-up mechanism picks up a sheet from a tray and feeds the sheet into a passageway. The sheet transporting mechanism transports the sheet picked up by the pick-up mechanism through and out of the passageway. The power source drives the pick-up mechanism. The power source includes a power output shaft for outputting power, and a first transmission gear for transmitting the power. The clutch includes a second transmission gear and a power coupling component. The second transmission gear and the first transmission gear are disposed coaxially. The power coupling component is coaxially disposed between the first transmission gear and the second transmission gear and coupled to the first transmission gear. The power coupling component reciprocates back and forth along an axis to selectively couple and drive the second transmission gear. The second transmission gear is coupled to the pick-up mechanism, and the power source selectively drives the pick-up mechanism through the clutch.

Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention.

FIG. 1 is a schematic illustration showing an automatic sheet feeding apparatus according to a preferred embodiment of the invention.

FIG. 2 is a partially pictorial view showing the automatic sheet feeding apparatus according to the preferred embodiment of the invention.

FIGS. 3 and 4 are partially schematic illustrations showing the clutch according to the preferred embodiment of the invention.

FIG. 5 is a partially pictorial view showing the automatic sheet feeding apparatus according to the preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

FIG. 1 is a schematic illustration showing an automatic sheet feeding apparatus 1 according to a preferred embodiment of the invention. FIGS. 2 and 5 are partially pictorial views showing the automatic sheet feeding apparatus 1 according to the preferred embodiment of the invention. Referring to FIGS. 1, 2 and 5, the automatic sheet feeding apparatus 1 of this embodiment includes a pick-up mechanism 10, a sheet transporting mechanism 20, a power source 30 and a clutch 40. Of course, the automatic sheet feeding apparatus 1 may further include a housing 90 and a scanning module 80 capable of moving back and forth in the housing 90.

The pick-up mechanism 10 may swing to pick up a sheet S from a tray 2 and feed the sheet S into a passageway 3. In this embodiment, the pick-up mechanism 10 includes a power input shaft 14 and an input gear 15. The input gear 15 is mounted on the power input shaft 14 and driven to rotate the power input shaft 14. The pick-up mechanism 10 further includes a separation roller 13 and a pick-up roller 12, both of which are rotatably mounted on a frame 11.

The separation roller 13 is mounted on the power input shaft 14 and is driven, by the power input shaft 14, to rotate. The pick-up roller 12 is driven, by the power input shaft 14, to rotate and move up and down.

The sheet transporting mechanism 20 transports the sheet S picked up by the pick-up mechanism 10 through and out of the passageway 3. The sheet transporting mechanism 20 includes a third transmission gear 25 and rollers 21, 22, 23 and 24, driven by the third transmission gear 25, for transporting the sheet S.

The power source 30 includes, without limitation to, a motor for driving the pick-up mechanism 10. The power source 30 includes a power output shaft 31 and a first transmission gear 32. The power output shaft 31 outputs power. The first transmission gear 32 mounted on the power output shaft 31 transmits the power. The power source 30 further includes an output gear 33, mounted on the power output shaft 31 and coupled to the first transmission gear 32 and the third transmission gear 25, for transmitting the power to the first transmission gear 32. Thus, the power source 30 may further drive the sheet transporting mechanism 20.

Referring to FIGS. 3 and 4, the clutch 40 includes a second transmission gear 41 and a power coupling component 43. The second transmission gear 41 and the first transmission gear 32 are disposed coaxially, which means, without limitation to, that the second transmission gear 41 and the first transmission gear 32 are mounted on the same rotating shaft or disposed on the same imaginary axis but mounted on different rotating shafts. The second transmission gear 41 meshes with the input gear 15 to transmit the power to the input gear 15. The power coupling component 43 is coaxially disposed between the first transmission gear 32 and the second transmission gear 41 and coupled to the first transmission gear 32. The power coupling component 43 reciprocates back and forth along an axis D2 to selectively couple and drive the second transmission gear 41.

The second transmission gear 41 is coupled to the pick-up mechanism 10. The power source 30 selectively drives the pick-up mechanism 10 through the clutch 40.

The clutch 40 may further include a clutch control mechanism 50 for moving the power coupling component 43 back and forth along the axis D2 to engage and disengage the power coupling component 43 from the second transmission gear 41.

The clutch control mechanism 50 includes a solenoid 52 and an arm member 51. A piston 52A of the solenoid 52 drives the arm member 51 to move in a direction D1 parallel to the moving direction of the power coupling component 43. The arm member 51 is driven by the solenoid 52 and connected to the power coupling component 43 to move the power coupling component 43.

The clutch control mechanism 50 may further include a compression spring 53, wrapping around the piston 52A, for providing a restoring force to the piston 52A.

Referring to FIGS. 3 and 4, the first transmission gear 32 includes a first internal meshing portion 32A. The power coupling component 43 engages the first internal meshing portion 32A. The second transmission gear 41 includes a second internal meshing portion 41A. The power coupling component 43 in the reciprocal motion selectively engages the second internal meshing portion 41A.

The power coupling component 43 includes a first ratchet portion 43A and a second ratchet portion 43B. The first internal meshing portion 32A is engaged with the first ratchet portion 43A and the second internal meshing portion 41A is engaged with the second ratchet portion 43B

Therefore, the power, coming from the power output shaft 31, may be transmitted to the separation roller 13 and the pick-up roller 12 through the output gear 33, the first transmission gear 32, the power coupling component 43, the second transmission gear 41, the input gear 15 and the power input shaft 14, and may also drive the rollers 21 to 24. When the pick-up roller 12 picks up many sheets at a time, the separation roller 13 and a frictional component 16 cooperate to separate one of the sheets from the sheets to ensure that only one single sheet is fed into the passageway 3. Next, the power coupling component 43 cuts off the power transmission between the first transmission gear 32 and the second transmission gear 41 such that the pick-up mechanism 10 stops but the sheet transporting mechanism 20 still operates. Therefore, the sheet S entering the passageway 3 is transported, by the rollers 21 and 22, past a region where the scanning module 80 can acquire the image of the sheet. Then, the rollers 23 and 24 transport the sheet S out of the passageway, and the scanning operation is thus finished.

In summary, the clutch is coaxially disposed between the first transmission gear and the second transmission gear in this invention. The first ratchet portion of the clutch permanently meshes with the first transmission gear, while the second ratchet portion of the clutch selectively meshes with the second transmission gear according to the control of the clutch control mechanism. The clutch operations achieved using these ratchet portions do not affect the precision of the external teeth of the transmission gear and preserve the intactness of the teeth, and each of the ratchet portions may be strengthened in structure and thus cannot be damaged. In addition, the clutch operations are performed in the horizontal direction and cannot be influenced by the gravity.

While the invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications. 

1. An automatic sheet feeding apparatus, comprising: a pick-up mechanism for picking up a sheet from a tray and feeding the sheet into a passageway; a sheet transporting mechanism for transporting the sheet picked up by the pick-up mechanism through and out of the passageway; a power source for driving the pick-up mechanism, the power source comprising: a power output shaft for outputting power; and a first transmission gear for transmitting the power; and a clutch, which comprises: a second transmission gear, wherein the second transmission gear and the first transmission gear are disposed coaxially; and a power coupling component coaxially disposed between the first transmission gear and the second transmission gear and coupled to the first transmission gear, wherein the power coupling component reciprocates back and forth along an axis to selectively couple and drive the second transmission gear; wherein the second transmission gear is coupled to the pick-up mechanism, and the power source selectively drives the pick-up mechanism through the clutch.
 2. The sheet feeding apparatus according to claim 1, wherein the pick-up mechanism comprises: a power input shaft; and an input gear mounted on the power input shaft and driven to rotate the power input shaft.
 3. The sheet feeding apparatus according to claim 2, wherein the second transmission gear meshes with the input gear to transmit the power to the input gear.
 4. The sheet feeding apparatus according to claim 2, wherein the pick-up mechanism comprises: a separation roller mounted on the power input shaft and driven by the power input shaft to rotate; and a pick-up roller driven by the power input shaft to rotate and move up and down.
 5. The sheet feeding apparatus according to claim 1, wherein the power source further comprises an output gear, mounted on the power output shaft and coupled to the first transmission gear, for transmitting the power to the first transmission gear.
 6. The sheet feeding apparatus according to claim 5, wherein the power source further drives the sheet transporting mechanism, the sheet transporting mechanism comprises a third transmission gear and a plurality of rollers, driven by the third transmission gear, for transporting the sheet, and the third transmission gear is coupled to the output gear.
 7. The sheet feeding apparatus according to claim 1, wherein the clutch further comprises a clutch control mechanism for moving the power coupling component back and forth along the axis to engage and disengage the power coupling component from the second transmission gear.
 8. The sheet feeding apparatus according to claim 7, wherein the clutch control mechanism comprises: a solenoid; and an arm member driven by the solenoid and coupled to the power coupling component to move the power coupling component.
 9. The sheet feeding apparatus according to claim 8, wherein a piston of the solenoid drives the arm member in a direction parallel to a moving direction of the power coupling component.
 10. The sheet feeding apparatus according to claim 9, wherein the clutch control mechanism further comprises: a compression spring, wrapping around the piston, for providing a restoring force to the piston.
 11. The sheet feeding apparatus according to claim 1, wherein: the first transmission gear comprises a first internal meshing portion, wherein the power coupling component engages the first internal meshing portion; and the second transmission gear comprises a second internal meshing portion, wherein the power coupling component in the reciprocal motion selectively engages the second internal meshing portion.
 12. The sheet feeding apparatus according to claim 11, wherein the power coupling component comprises: a first ratchet portion; and a second ratchet portion; wherein the first internal meshing portion is engaged with the first ratchet portion and the second internal meshing portion is engaged with the second ratchet portion. 